Question

I’m trying to feed an array with fscanf() while looping through a file containing a list of integers, n integers long. It seems that I need to use malloc and/or potentially realloc. I’ve heard that the malloc command takes a noticeable amount of execution time and that it’s best to over-allocate. Would someone mind helping me out with understanding the building blocks of accomplishing this end?

Disclaimer: I’m new to C.

Answer 1

No, what you’ve heard is misleading (at least to me). malloc is a just a function, and usually a fast one.

• Most of the time it does all of its job in user-space. It “overallocates” so you don’t have to
• The bookkeeping (the linked list with free blocks etc.) is highly optimized since virtually everyone uses malloc

It’s unrealistic to think you can easily beat malloc at this game. I am sorry if this doesn’t answer your question (which was pretty general) but you have to realize there is no (spoon) optimization you can easily implement.